Virginia Woolf
once famously said, "A woman must have money and a room of her own if she
is to write fiction." It might as accurately be said that a scientist must
have funding and a lab of her/his own. In the summer of 2004 the nearly 50 Carl
Sagan Center (CSC) scientists of the SETI Institute moved to a new facility
with three vacant laboratory spaces and instantly acquired entire new vistas of
research. One of those laboratories has been fully outfitted and operational
for nearly six months now. That has made all the difference to Dr. Rocco Mancinelli
and the other astrobiologists who analyze their samples in the Microbial
Ecology and Molecular Microbiology Laboratory--Lab 2 or simply 'Rocco's lab" to
friends.
Astrobiologists,
those cross disciplinary scientists dedicated to investigating the broad
question of life in the universe, often study extremophiles, organisms that
live at the edges of what life is known to tolerate. Bubbling acidic hotsprings,
deep ocean blacksmokers, and deep dark caves are the sources of some
researchers' extremophiles-those that love high temperatures, great pressures
or live without light, but Dr. Mancinelli gets his microbes wherever there is
lots of salt. Halophiles are salt lovers and thrive where salt abounds in
concentrations that would kill most ordinary organisms. Halophiles are
incredibly robust creatures.
Mancinelli has flown them in the vacuum and freezing temperatures of space, exposed to intense radiation, and most of them
returned alive and well. He regularly collects them from salty mountain lakes
high in the Bolivian Andes, but he can also find them right next door in the
San Francisco Bay. In fact, halophiles are found in all waters with high salt
content, that is, from 15% up to the saturation point. There are halophiles in
all three known branches of living systems (domains of life), that is, the Archea,
organisms having characteristics of both the Bacteria and the Archaea,
Bacteria, the most prevalent organisms on earth and the Eukaryotes, which
include the most complex organisms on earth including you and me. Because these
halophilic microbes are so ubiquitous and so robust, they are great candidates
for the kind of organism that might once have lived or possibly even still
survives, on Mars.
Once
samples arrive in the Halophile Lab, they are studied to see what they contain.
Lake or seawater samples are usually stored at 4° in the refrigerator before
analyses begin and then a bit is "innoculated" into a flask of halobroth,
a rich salty solution that encourages the organisms to thrive and multiply. A
bit of this resulting mixture is then "streaked" onto a set of Petri
dishes or "plated" with more halobroth, and colonies of organisms
often result. In this way, often simply through visual inspection, a single
organism can be identified, reintroduced to a halobroth flask, cultured and
plated and ultimately isolated for further study. Once a single organism is
isolated, the real fun begins.
Some of the
halophilic organisms are incubated at a range of temperatures, such as 4°, 12°,
ambient and 37° C to see how they survive and grow. Mostly, they do quite well,
growing more slowly at the low temperatures and growing more rapidly at the
warm temperatures. Some of them are irradiated with ultra violet (UV) light in
the controlled laboratory setting and then carefully studied to see how they
are affected and to gain clues to their survival strategies, whether it be from
the salt itself or from some clever genetic mechanism. Some of them are really
put through their paces with freeze and thaw cycles. Most of them still manage
to survive even this sort of radical environmental change. Again, they are
carefully studied to see just what constitutes the survival mechanism.
While
Rocco's Lab is not his first, by any means, all these carefully controlled
studies are greatly facilitated by having an on-site laboratory dedicated to
the study of microbial ecology and under the management of a single researcher.
The team takes strict care of both the organisms and the lab itself. Having a
lab dedicated to specific aspects of microbial ecological research has greatly
advanced the team's ability to make progress. In fact, Dr. Mancinelli and his
team are about to embark on a next-steps series of experiments to complement
the characterization studies of the halophiles: studies of the nitrogen cycle,
how nitrogen is fixed and released in soils in dry, high altitude Mars
analogues. Mancinelli believes that nitrogen, a critical element for biologic
systems, may be a key bio-marker. Now that he has a lab of his own, he might
just find out.
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